Reduce time between editing contacts and seeing those changes in the app

* Move a couple lib methods behind our own interface
* Cache parsing phone numbers since it's expensive
* I considered caching formatting as well since it's also a bit
  expensive, but generating an appropriate cache key was actually slower
  than the raw implementation.

// FREEBIE

src/Contacts/PhoneNumber.m

@@ -16,7 +16,7 @@ static NSString *const RPDefaultsKeyPhoneNumberCanonical = @"RPDefaultsKeyPhoneN
     OWSAssert(text != nil);
     OWSAssert(regionCode != nil);
 
-    NBPhoneNumberUtil *phoneUtil = [PhoneNumberUtil sharedUtil].nbPhoneNumberUtil;
+    PhoneNumberUtil *phoneUtil = [PhoneNumberUtil sharedUtil];
 
     NSError *parseError   = nil;
     NBPhoneNumber *number = [phoneUtil parse:text defaultRegion:regionCode error:&parseError];

src/Contacts/PhoneNumberUtil.h

@@ -26,4 +26,9 @@
 
 + (instancetype)sharedUtil;
 
+- (NBPhoneNumber *)parse:(NSString *)numberToParse defaultRegion:(NSString *)defaultRegion error:(NSError **)error;
+- (NSString *)format:(NBPhoneNumber *)phoneNumber
+        numberFormat:(NBEPhoneNumberFormat)numberFormat
+               error:(NSError **)error;
+
 @end

src/Contacts/PhoneNumberUtil.m

@@ -6,10 +6,12 @@
 #import "ContactsManagerProtocol.h"
 #import "FunctionalUtil.h"
 #import "Util.h"
+#import <libPhoneNumber-iOS/NBPhoneNumber.h>
 
 @interface PhoneNumberUtil ()
 
 @property (nonatomic, readonly) NSMutableDictionary *countryCodesFromCallingCodeCache;
+@property (nonatomic, readonly) NSCache *parsedPhoneNumberCache;
 
 @end
 
@@ -32,6 +34,7 @@
     if (self) {
         _nbPhoneNumberUtil = [[NBPhoneNumberUtil alloc] init];
         _countryCodesFromCallingCodeCache = [NSMutableDictionary new];
+        _parsedPhoneNumberCache = [NSCache new];
 
         OWSSingletonAssert();
     }
@@ -39,6 +42,37 @@
     return self;
 }
 
+- (nullable NBPhoneNumber *)parse:(NSString *)numberToParse
+                    defaultRegion:(NSString *)defaultRegion
+                            error:(NSError **)error
+{
+    NSString *hashKey = [NSString stringWithFormat:@"numberToParse:%@defaultRegion:%@", numberToParse, defaultRegion];
+
+    NBPhoneNumber *result = [self.parsedPhoneNumberCache objectForKey:hashKey];
+
+    if (!result) {
+        result = [self.nbPhoneNumberUtil parse:numberToParse defaultRegion:defaultRegion error:error];
+        if (result) {
+            [self.parsedPhoneNumberCache setObject:result forKey:hashKey];
+        } else {
+            [self.parsedPhoneNumberCache setObject:[NSNull null] forKey:hashKey];
+        }
+    }
+
+    if ([result class] == [NSNull class]) {
+        return nil;
+    } else {
+        return result;
+    }
+}
+
+- (NSString *)format:(NBPhoneNumber *)phoneNumber
+        numberFormat:(NBEPhoneNumberFormat)numberFormat
+               error:(NSError **)error
+{
+    return [self.nbPhoneNumberUtil format:phoneNumber numberFormat:numberFormat error:error];
+}
+
 // country code -> country name
 + (NSString *)countryNameFromCountryCode:(NSString *)countryCode {
     NSDictionary *countryCodeComponent = @{NSLocaleCountryCode : countryCode};